A Process For The Preparation Of Platform Chemicals From Sugar Using Acid Catalyst

ABSTRACT

A process is provided for the preparation of value added chemicals such as ethyl levulinate from a glucose or other sugars, catalyzed by a mixture of a Lewis acid catalyst and a Bronsted acid catalyst.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a national-stage application under 35 U.S.C. § 371of International Application No. PCT/IN2020/050041, filed Jan. 15, 2020,which International Application claims benefit of priority to IndianApplication No. 201911001842, filed Jan. 16, 2019.

TECHNICAL FIELD

The present disclosure relates to a one step process for the preparationof various value added platform chemicals from sugar. The presentdisclosure more particularly relates to a process for the preparation ofvalue added chemicals such as ethyl levulinate from glucose or othersugars catalyzed by a mixture of a Lewis and Bronsted acid catalyst.

BACKGROUND

Biomass derived biofuels and biochemical is an area where substantialresearch is in progress. Amongst the various biochemicals, levulinicacid is a molecule of global interest, and its further conversion toalkyl levulinate will find applications as plasticizers, herbicides,perfumery, fuel additives and oxygenators for diesel. Biofuel suffersfrom a limitation to its use in cold regions due to high freezing pointbetween 3-7° C. The introduction of additives such as ethyl levulinate(EL), which has a freezing point of −79° C., improves properties ofbiodiesel such as cloud point, pour point, and cold filter pluggingpoint. Further, Ethyl levulinate is a sulphur free additive which can bedirectly blended with normal diesel or biodiesel or can be used as 100%fuel to replace petroleum diesel.

There are reports of synthesizing EL from sugars, bypassing levulinicacid employing both homogeneous and heterogeneous catalysts. H-USY hasbeen used widely along with a mineral acid and yields are reported up tonearly 52%. The solid loading initially varies between 30-50 g/lt inthese reports. While homogeneous catalysts suffer from need for tediousseparation processes, heterogeneous catalysts used till date have poorSi:Al ratio or low surface area. Also, some of them exhibit poorcatalytic activity in the presence of high concentration of sugars.

The article titled, “Direct transformation of carbohydrates to thebiofuel 5-ethoxymethylfurfural by solid acid catalysts” by Hu Li, et al.published in Green Chemistry, 2016, 18, 726-734 reports the conversionof glucose to EMF was examined over several solid acid catalysts inethanol between 96 and 125° C. Among the catalysts employed,dealuminated beta zeolites [DeAl—H-beta-12.5 (700)] gave a moderateyield of EMF (37%) in a single step catalytic process. A combinedcatalytic system consisting of H-form zeolite and Amberlyst-15 was foundto be more efficient for the transformation of glucose to EMF (46%) viaa one-pot, two-step reaction protocol.

The article titled, “One-pot production of a liquid biofuelcandidate—Ethyl levulinate from glucose and furfural residues using acombination of extremely low sulfuric acid and zeolite USY” by ChunChang et al. published in Fuel, 2015, 140, Pages 365-370 reports theconversion of glucose to ethyl levulinate in ethanol medium.Experimental results showed that the combination of extremely lowsulfuric acid and zeolite USY can be used as an effective catalyticsystem for one-pot EL production from glucose. The ethyl levulinateyield of 51.47% from glucose can be obtained at 180° C. and 120 min inthe mixed acid system comprising of 0.1% sulfuric acid and 2.0% USY.Combination of extremely low sulfuric acid and USY is efficient for ELproduction. Higher EL yield of 51.47% from glucose can be obtained inthe mixed acid system. Higher EL yield of 18.68% from FRs can beobtained in the mixed acid system.

US2015/0045576 A1 discloses methods have been developed to convertsaccharides into value-added products such as alkyl lactates, lacticacid, alkyl levulinates, levulinic acid, and optionally alkyl formateesters and/or hydroxymethylfurfural (HMF). Useful catalysts includeLewis acid catalysts and Bronsted acid catalysts including mineralacids, metal halides, immobilized heterogeneous catalysts functionalizedwith a Bronsted acid group or a Lewis acid group, or combinationsthereof. The saccharides are contacted with the catalyst in the presenceof various alcohols.

In prior arts, by using acid catalysts, as the substrate loading isincreased, the yield obtained becomes less.

Thus, there is a need in the art to provide a more efficient process forthe synthesis of EL. This may be accomplished by making a provision fora more efficient catalytic system to catalyse the conversion of sugarsto EL.

Main objective of the present disclosure is to provide a one stepprocess for the preparation of various value added chemicals from sugar.

Another objective of the present disclosure is to provide a one stepprocess for the preparation of various value added chemicals from sugarin presence of a mixture of Lewis and Bronsted acid catalyst.

SUMMARY

Accordingly, the present disclosure provides a one step process forconversion of sugars to corresponding platform chemicals comprisingreacting sugar with a physical mixture of Lewis and Bronsted acidcatalyst at a temperature in the range of 100-250° C. for 0.5 h to 10 hin alcohol.

In an embodiment, the present disclosure provides a one step process forconversion of sugars to corresponding platform chemicals comprisingreacting sugar with a physical mixture of H-USY and SnO₂ catalyst at atemperature in the range of 100-250° C. for 0.5 h to 10 h in alcoholwherein the yield of the reaction is in the range of 80 to 85%.

Acronyms

EL: Ethyl levulinate

EMF: 5-Ethoxymethyl Furfural

EL A: Ethyl lactate

LA: Levulinic acid

H-USY: Acid form of zeolite

B/L ratio: Bronsted/Lewis acid ratio

S/W ratio: Strong to weak acidity ratio

H-beta: Zeolite type of beta topology

H-Y: Zeolite type of Y topology

H-ZSM-5: Zeolite Socony Mobil-5

SB A-15: SANTA BARBARA AMORPHOUS

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: XRD pattern of (a) SnO₂, TiO₂, and ZrO₂ and (b) H-USY andSn-beta.

FIG. 2: Ammonia TPD of H-USY, Physical combinations of H-USY and SnO₂.

FIG. 3: Ammonia TPD of SnO₂, TiO₂, and ZrO₂ and Sn-beta

FIG. 4: Pyridine IR of H-USY and physical combination of H-USY:SnO₂(95:05).

FIG. 5: SEM images of (A) H-USY, (B) SnO₂ (C) Physical combination ofH-USY:SnO₂ (95:05) (D) Physical combination of H-USY:SnO₂ (80:20)

FIG. 6: Effect of % SnO₂ on yields of (a) EL, (b) intermediate sugars(mannose, glucosides, and fructosides), (c) EMF, (d) ELA catalyzed byH-USY: SnO₂, glucose concentration=50 g/L, catalyst loading=50% wrtglucose concentration, 12 mL of ethanol, 800 rpm, 160° C., and 3 h.

FIG. 7: Effect of catalyst (H-USY+SnO₂) loading with respect to glucoseconcentration on yields of EL, intermediate sugars, EMF, and ELAcatalyzed by H-USY/SnO₂ (95:05), glucose concentration=50 g/L, 12 mLethanol, 800 rpm, 160° C., and 3 h.

FIG. 8: Effect of variation in glucose concentration on % yield of EL,intermediate sugars, EMF, and ELA catalyzed by H-USY/SnO₂ (95:05),catalyst loading=50% with respect to glucose concentration, 12 mLethanol, 800 rpm, 160° C., and 3 h.

FIG. 9: Effect of temperature on yields of EL, intermediate sugars, EMF,and ELA catalyzed by H-USY/SnO₂ (95:05), glucose concentration=50 g/L,catalyst loading=50% with respect to glucose concentration, 12 mLethanol, 800 rpm, and 3 h.

FIG. 10: Effect of time over % yields on EL, intermediate sugars, EMF,and ELA catalyzed by H-USY/SnO₂ (95:05), glucose concentration=50 g/L,catalyst loading=50% with respect to glucose concentration, 12 mLethanol, 800 rpm, and 180° C.

DETAILED DESCRIPTION

Various embodiments will now be described in detail in connection withcertain preferred and optional embodiments, so that various aspectsthereof may be more fully understood and appreciated.

The present disclosure provides a one step process for conversion ofsugars to corresponding platform chemicals comprising reacting sugarwith a physical mixture of Lewis and Bronsted acid catalyst at atemperature in the range of 100-250° C. for 0.5 h to 10 h in alcoholwherein the yield of the reaction is in the range of 80 to 85%.

In an embodiment, the present disclosure provides a one step process forconversion of sugars to corresponding platform chemicals comprisingreacting glucose in the presence of a physical mixture of H-USY and SnO₂in the ratio of 5:95 to 95:5 at a temperature in the range of 100-250°C. for 0.5 h to 10 h in ethanol to obtain ethyl levulinate wherein theyield of the reaction is in the range of 80 to 85%.

The sugar is selected from the group consisting of glucose, galactose,fructose, xylose, sucrose, lactose, maltose, trehalose, sorbitol, andmannitol, alone or combinations thereof, preferably glucose.

The Platform chemicals may be defined as value added chemicals derivedfrom natural substrates and are selected from ethyl levulinate, methyllevulinate, 5-HMF, Levulinic acid, Gamma-Valero Lactone; 5-Hydroalkylfurfural preferably 5-Ethoxymethyl furfural, Ethyl Lactate;5-Methoxymethyl furfural; Methyl Lactate, butyl levulinate, propyllevulinate, hexyl levulinate, octyllevulinate, butyl lactate, propyllacatate, hexyl lactate, octyl lactate, butyl furfural, propyl furfural,hexyl furfural and octyl furfural.

The 5-Hydroalkyl furfural is Cl-CIO alkyl furfural and is selected from5-methyl furfural, 5-ethyl furfural, 5-propyl furfural, 5-butylfurfural, 5-pentyl furfural, 5-hexyl furfural, 5-heptyl furfural,5-octyl furfural, 5-nonyl furfural, 5-decyl furfural. In particularlypreferred embodiment, 5-ethyl methyl furfural is used.

The sugar loading for the process of synthesis of platform chemicals mayvary between 30-83 g/lt and the catalyst loading is in the range of30-100% with respect to sugar loading.

The Lewis acid is selected from Sn-beta, TiO₂, ZrO₂ and SnO₂.

The Bronsted acid is selected from H-USY, H-beta; H-Y; H-ZSM-5; allsmall/medium/large pore zeolites; SB A-15; its hierarchical form;modification by sulphonation/phosphonation and combination of it.

The catalyst for the synthesis of value added chemicals is a physicalmixture of 95:5 of H-USY: SnO₂, wherein H-USY is commercially availableand SnO₂ is synthesized as exemplified herein. The surface area ofsurface area of H-USY is in the range of 600 to 800 m²/gm and Si:Alratio is in the range of 12 to 30.

The alcohol is selected from methanol; ethanol; propanol; butanol;hexanol; octanol, Cl to C10 alcohols and their mixture.

In the present disclosure, the catalytic direct conversion of glucose toEL without the formation of levulinic acid and aimed to handle higherglucose loading which follows the green chemistry principles such asutilization of renewable materials and omission of derivatization stepsand output-led design.

FIG. 1 depicts XRD patterns of (a) SnO₂, TiO₂, and ZrO₂ and (b) H-USYand Sn-beta.

In FIG. 1, (a) illustrates the typical XRD patterns of SnO₂, TiO₂, andZrO_(2.) The XRD pattern of SnO₂ exhibits diffraction peaks at 2theta=26.6, 33.9, 38.0, 51.8, 57.9, 62.0, 66.0, 71.3, and 78.7indicating a tetragonal rutile structure. The XRD pattern of TiO₂ showsdiffraction peaks at 2 theta=25.4, 36.9, 37.7, 38.5, 48.01, 53.8, 55.03,and 62.07 which confirms the TiO₂ anatase structure. The XRD pattern ofZrO₂ exhibits diffraction peaks at 2 theta=24.2, 28.2, 30.3, 31.4, 35.3,40.9, 50.5, 54.1, 55.6, 60.1, 63.0, 65.6, and 74.9, majorly tetragonalphase accompanied with a smaller portion of the monoclinic phase. InFIG. 1, (b) shows a typical XRD pattern of H-USY and Sn-beta for 2 thetarange of 5°-50°. The XRD pattern of H-USY and Sn-beta indicates a purecrystalline phase of faujasite and beta.

The catalyst comprising a physical mixture of H-USY and SnO₂ wascharacterized, and referring to FIG. 2, the figure illustrates ammoniaTPD of H-USY, physical combinations of H-USY and SnO₂, as SnO₂ mixedwith H-USY as a physical mixture. Overall acidity of the catalystincludes combination of weak (100-300° C.) and strong (300-550° C.) acidsites. The acidity is marginally reduced for H-USY:SnO₂ of 95:5, whereasit substantially decreased for a mixture of 80:20.

FIG. 3 depicts TPD profiles for weak and strong acid sites of the Lewisacidic catalyst such as Sn-beta; ZrO₂; TiO₂; and SnO₂. ZrO₂ and Sn-betashowed a single ammonia desorption peak in a temperature range of100-400° C., which corresponds to weak acidity. The SnO₂ displaying twoconsiderable ammonia desorption peaks in 100-250 and 300-600° C.indicate weak and strong acidity, respectively. It is observed thatstrong acidity has contributed majorly in SnO₂ as compared to weakacidity, wherein TiO₂ was observed to be the lowest acidic. Among thestudied catalysts, only SnO₂ was found to have strong acid sites, whichare responsible for the reaction of glucose to EL.

Table 1 elaborates on the ratio of strong to weak acidity and specificto its B/L ratio for parent H-USY and physical combinations ofH-USY/SnO₂. The introduction of SnO₂ increases the strong acid sites ofthe overall combination (HUSY/SnO₂) and thereby the strong/weak acidity(S/W) ratio from 1.24 to 2.94, whereas B/L ratio was found to decreasefrom 0.94 to 0.60. This confirmed that by the introduction of SnO₂, thecontribution of Lewis acid sites increases, which is especially requiredfor isomerization of glucose to fructose and partly for the ethanolysisstep. Among the Lewis acid catalysts, the total acidity trend is ZrO₂(0.46 mmol/g)>SnO₂ (0.37 mmol/g)>Sn-beta (0.26 mmol/g)>TiO₂ (0.05mmol/g). However, the ZrO₂ has weak Lewis acid sites, whereas SnO₂ hasstrong acid sites.

TABLE 1 Acidity Properties of Different Catalyst Total acidity Sr. No.Catalyst Strong/weak B/L (mmol/g) 1 H-USY 1.24 0.94 0.74 2 H-USY/SnO₂(95:05) 1.30 0.75 0.70 3 H-USY/SnO₂ (80:20) 2.94 0.60 0.64 4 Sn-beta0.26 5 SnO₂ 0.37 6 TiO₂ 0.05 7 ZrO₂ 0.46

FIG. 4 depicts Pyridine IR of H-USY and physical combination ofH-USY:SnO₂ (95:05). Pyridine-IR spectra exhibits Lewis acidity at 1443cm⁻¹ and Bronsted and Lewis at 1490 and 1544 cm⁻¹ for only Bronstedacidity, respectively.

The size and morphology of H-USY and SnO₂ and the physical combinationof H-USY and SnO₂ were studied using SEM, and the SEM images areprovided in FIG. 5. H-USY exhibited cubic- and hexagonal-shapedparticles having a size of 0.5-0.75 mm, whereas SnO₂ showed agglomeratesof spherical-shaped particles with a size of around 0.1 mm. The physicalcombination of H-USY and SnO₂ showed a mixed morphology of H-USY andSnO₂.

The structural properties of H-USY and a physical combination of H-USYand SnO₂ are provided in Table 2. In comparison with H-USY, the BETsurface area of the physical combination of H-USY and SnO₂ was observedto be in a decreasing trend with a percent increase in SnO₂concentration. Whereas pore volume and pore diameter were observed to beconstant throughout which it reveals that additional SnO₂ in physicalcombination does not hinder or block the pores of H-USY.

From Table 2, it is observed that, the combination of H-USY/SnO₂ (80:20)gives a maximum EL yield of 57% (Table 2, entry 6) as compared to plainHUSY (45%). This enhancement of EL yield is due to additional strongLewis acid sites generated from SnO₂. Among Lewis acidic catalysts, SnO₂is found to be more active than others because SnO₂ has morecontribution of strong Lewis acid sites than weak, whereas others haveonly weak Lewis acidity (FIGS. 3, 4, and Table 1). In all cases, the EMFformation is in the range of 3-10%, whereas ELA is in the range of 1-4%except plain Sn-beta (18%) (Table 2, entry 2), which is the Lewis acidiccatalyst with the structure of beta, which leads to the formation of ELAby retro-aldol condensation reaction (Lewis acidic reaction).

TABLE 2 Preparation of platform chemicals using different CatalystCatalyst % EL % EMF % ELA 1 H-USY 45 3 0 2 Sn-Beta 0 10 18 3 H-USY +Sn-Beta 51 8 4 4 H-USY + TiO₂ 40 5 0.4 5 H-USY + ZrO₂ 48 6 1 6 H-USY +SnO₂ 57 6 1

In other Lewis acidic catalysts, the surface reaction is predominant asit is a structure-less material. Overall, the combination of H-USY/SnO₂(80:20) having higher S/W ratio (2.94), with low B/L ratio (0.60) havingstrong Lewis acidity because of the presence of SnO₂ reflected to behighly active with the EL yield of 57% at the minimum formation of EMF(6%) and ELA (1%).

Table 2 confirmed that the EMF formation is <10% in all of thecombination of H-USY (80%) with other L acidic catalysts (20%) such asTiO₂; SnO₂; Sn-beta; and ZrO₂.

From FIG. 6 it is observed that the concentration of strong Lewis acidsites in combination with H-USY and SnO₂ changed with an increase inSnO₂ percent from 0 to 30%. In case of zeolite H-USY, an EL yield ofabout 45% was obtained along with intermediate sugars, whereas when thereaction is catalyzed with a combination of H-USY and SnO₂ (97:03), theEL yield is observed to be increased up to 57%. With the addition ofSnO₂, strong Lewis acid sites (FIGS. 3 and 4) are utilized to convertformed glucosides to fructosides, which leads to the formation of EL. Asthe quantity of SnO₂ is increased from 3 to 5%, a sharp increase in ELyield from 57 to 64% was noticed, which is governed by the conversion ofremaining available glucosides to fructosides. Further increment in SnO₂to 7% EL yield is observed to be identical to that of 5%. At 10% SnO₂loading, the EL yield decreased to 55% with a slight increment inintermediate sugars. A drop in the EL yield might be because ofinsufficient amount of Bronsted acid sites of HUS-Y in combination withSnO₂ (90:10).

Above 10% SnO₂ loading, overall Bronsted acidity decreases because ofthe lesser contribution of H-USY in the combination, which promotes themarginal increment in the EMF formation from 5 to 8%; however, furtherconversion of EMF to EL is observed to be limited because of the lessavailability of Bronsted acidity. Moreover, almost identical ELAformation of 1% is found throughout different concentrations of SnO₂.The increase in EL yield with the addition of SnO₂ is mainly because ofthe improvement in Lewis acidity, especially strong Lewis acidity whichis responsible for enhancement in the rate of isomerization reactionthan plain H-USY, thereby increasing the overall rate of reaction and sothe yield. However, excess strong Lewis acidity is also not advantageousbecause it reduces the Bronsted acidity which is required fordehydration of fructosides to EMF and alcoholysis of EMF to EL reaction.Thus, a proper combination of B/L (0.75) and S/W (1.30) (Table 1) iscritical for this reaction, which suits well with 5-7% of SnO₂ and H-USYhaving properties such as surface area=780 m²/g and Si/Al=15.

FIG. 7 depicts the effect of catalyst loading HUSY/SnO₂ (95:05) onproduct yield. As catalyst loading increases from 30 to 50%, a sharpincrease in the EL yield from 46 to 65% is observed.

FIG. 8 depicts the effect of glucose concentrations on the yield of EL,EMF, and ELA. Up to a glucose concentration of 50 g/L, keeping theethanol concentration in a reaction medium the same, the EL yield isobserved to be identical at 65%. Above 50 g/L glucose concentration, themarginal decrease in EL yield from 65 to 60% is observed up to 83 g/Lglucose concentration. Above 83 g/L glucose concentration, the EL yieldis decreased to 41% at 150 g/L glucose concentration. The increasingtrend of EMF formation and the identical formation of ELA is noted asglucose concentration increases. Also, the decreasing trend ofintermediate sugar formation with the increasing glucose concentrationin reaction mixture is noticed.

FIG. 9 depicts the effect of temperature on % yield of EL, EMF, and EL Afrom 160 to 190° C. As the temperature increases from 160 to 180° C.,with decrement in intermediate sugars, the EL yield is observed to beincreased from 65 to 81%, which is substantial and highest so far.

FIG. 10 depicts the effect of time from 0.5 to 7 h on the yield of EL,EMF, ELA, and intermediate sugars. Up to a reaction time of 3 h, the ELyield is found to be on an increasing trend from 60 to 81% with adecrease in intermediate sugars and EMF along with a slight increase inELA formation. At higher temperature of 180° C., when the reaction timeprolonged for more than 3 h, the substantial decrease in the EL yieldfrom 81 to 73% was observed.

TABLE 3 Effect of catalyst (HUSY + SnO₂) loading w.r.t. glucoseconcentration on yields of EL HMF, ELA Catalyzed by H-USY:SnO₂ (95:05)Catalyst Loading EL Yield EMF Yield ELA Yield (%) (mol %) (mol %) (mol%) 30% 46.08 2.96 0.33 50% 64.5 3.74 0.52 70% 69.14 2.13 0.73 100% 68.06 1.65 0.97 Reaction conditions: glucose concentration = 50 g/L, 12mL ethanol, 800 RPM, 160° C., 3 h

TABLE 4 Glucose concentration: Effect of variation in glucoseconcentration on % yield EL, EMF and ELA catalyzed by H-USY:SnO₂ (95:05)Glucose concentration EL Yield EMF Yield ELA Yield (g/L) (mol %) (mol %)(mol %) 33.33 64 2.71 0.47 50 64.75 4.67 0.63 66.66 60.8 4.13 0.56 7561.37 6.92 0.65 83.33 60 5.7 0.62 100 53.66 5.45 0.52 150 40.94 7.1 0.62Reaction condition: catalyst loading = 50% w.r.t. glucose concentration,12 mL ethanol, 800 RPM, 160° C., 3 h

TABLE 5 Effect of Temperature on yields of EL, EMF, ELA Catalyzed byH-USY:SnO₂ (95:05) EL Yield EMF Yield ELA Yield Temperature (mol %) (mol%) (mol %) 160 64.75 4.67 0.63 170 70.09 2.08 0.85 180 81.1 0.77 1.26190 64.02 0.225 1.2 Reaction condition: concentration = 50 g/L, catalystloading = 50% w.r.t. glucose concentration, 12 mL ethanol, 800 RPM, 3 h

TABLE 6 Effect of time over % yield EL, EMF and ELA catalyzed byH-USY:SnO₂ (95:05) EL Yield EMF Yield ELA Yield Time (mol %) (mol %)(mol %) 0.5 60.32 4.76 0.51 1 64.6 5.07 0.77 2 68.07 1.63 0.95 3 81.10.77 1.26 5 77.6 0.125 1.28 7 71.55 0.075 1.285 Reaction condition:glucose concentration = 50 g/L, catalyst loading = 50% w.r.t. glucoseconcentration, 12 mL ethanol, 800 RPM, 180° C.

The reusability of catalyst H-USY (95%) and SnO₂ (5%) was investigatedover the identical optimized conditions (glucose concentration=50 g/L,50% catalyst loading, 180° C., 3 h).

After the first run, the catalyst was washed with acetone and thencalcined at 550° C. and then was reused for the next reaction. Thecatalyst was observed to be active up to 4 runs with almost constantglucose conversion of 90% (±3%) and EL yield of 81% (±3%) over asynergetic combination of H-USY and SnO₂.

In various embodiments, the H-USY used has the following properties:surface area 780 m²/g; Si/Al ratio=15; strong to weak acidity of 1.24,and Bronsted to Lewis acidity ratio of 0.94, with total acidity of 0.74mmol/g of catalyst. These properties of H-USY are not reported forglucose to ethyl levulinate. In various embodiments, the, optimumcatalyst is a physical combination of H-USY (95%)+SnO₂ (5%) whichchanges the properties of the overall invented catalyst to: strong toweak acidity ratio of 1.30; Bronsted to Lewis acidity ratio of 0.75;total acidity of 0.70 mmol/g of catalyst. This combination is notreported for glucose to ethyl levulinate so far.

This particular combination of catalyst can handle glucose concentrationup to 50 gm/L (50 gm of glucose in 1 L of ethanol), which is higher thanreported. Reported optimum glucose concentration is 20 g/L. This meansthat, present catalyst can handle more substrate concentration withimproved ethyl levulinate yield of 81%, which increases the overallprocess productivity.

EXAMPLES

Following examples are given by way of illustration therefore should notbe construed to limit the scope of the disclosure.

Procurement Raw Materials:

Zeolite H-USY: The commercial H-USY zeolite (CBV 720) with Si/Al=15 andsurface area=780 m²/g was procured from zeolyst Internationals,Netherlands

Example 1 General Example for Preparation of Ethyl Levulinate

Glucose concentration in ethanol from 33.33 g/L with physical mixture ofH-USY and SnO₂ catalyst loading of 70 wt % with respect to glucose wassubjected to thermal treatment at temperature range of 160° C. fordifferent time span of 7 h. All the reactions were carried out at 800RPM to overcome external mass transfer limitations during the reaction.The reaction mixture was cooled in cold water bath to reach 30 degreefollowed by separation from the catalyst by centrifugation. Supernatantreaction mixture was diluted with ethanol and injected into GasChromatography (GC) system (chemito-1000) equipped with TR capillarycolumn (30 mm×0.32 mm×0.25 mm) and Flame Ionization Detector withcarrier gas N₂ with flow rate 1.0 mL min⁻¹. Injection port temperature,oven temperature and detector temperature were programmed at 230° C., 50to 280° C. with heating rate 20° C. min⁻¹ and 260° C. for feed andproduct analysis. Yields of EL, EMF and ELA are calculated by followingequations:

% Yield of EL=(Moles of EL/Moles of Glucose)*100%

Yield of EMF=(Moles of EMF/Moles of Glucose)*100%

Yield of ELA=(Moles of ELA/Moles of Glucose)*100

Example 2 Preparation of SnO₂

50 g of CTAB (cetyltrimethyl ammonium bromide) was added to 500 mL DMwater and then stirred for 1 hour. Another aqueous solution of 50 gSnCl₄.5H₂O was prepared in 500 mL water under constant stirring.Homogenous solution of 80 mL ammonium hydroxide in 80 mL DM water wasmixed with previously prepared CTAB solution. Aqueous solution of SnClwas added in CTAB and NH₄OH mixture. After complete addition ofSnCl₄.5H₂O solution, the slurry was stirred for 4 h and afterwards keptfor aging for 48 h at 30 degrees temperature. Slurry was then filteredand washed with DM water and acetone. Wet cake was kept in oven at 100°C. for 12 h and then calcined at 550° C. for 12 h with rate of 1°C./min.

Advantages

1. Green and eco-friendly process

2. Simple process to synthesize catalyst

3. Higher yields of value added platform chemicals

4. Catalyst can tolerate higher concentration of sugars

5. Catalyst can be used for any type of sugars; C1-C10 alcohols andtheir mixtures.

1-9. (canceled)
 10. A one-step process for converting sugars to platformchemicals, the one-step process comprising: reacting a sugar with aphysical mixture of a Lewis acid catalyst and a Bronsted acid catalystat a temperature from 100° C. to 2000° C. for 0.5 h to 7 h in an alcoholto obtain the platform chemicals with a reaction yield from 60% to 85%.11. The one-step process of claim 10, wherein the sugar is selected fromthe group consisting of glucose, galactose, fructose, xylose, sucrose,lactose, maltose, trehalose, sorbitol, mannitol, and combinationsthereof.
 12. The one-step process of claim 10, wherein the platformchemicals are selected from the group consisting of ethyl levulinate,methyl levulinate, 5-HMF, levulinic acid, gamma-valerolactone,5-hydroalkyl furfural, 5-ethoxymethyl furfural, ethyl lactate,5-methoxymethyl furfural, methyl lactate, butyl levulinate, propyllevulinate, hexyl levulinate, octyl levulinate, butyl lactate, propyllactate, hexyl lactate, octyl lactate, butyl furfural, propyl furfural,hexyl furfural, and octyl furfural.
 13. The one-step process of claim10, wherein the sugar is loaded at from 30 g/L to 83 g/L and thephysical mixture of Lewis acid catalyst and Bronsted acid catalyst isloaded at 30% to 100% with respect to the sugar loading.
 14. Theone-step process of claim 10, wherein the Lewis acid catalyst isselected from the group consisting of Sn-beta, TiO₂, ZrO₂, and SnO₂. 15.The one-step process of claim 10, wherein the Bronsted acid catalyst isselected from the group consisting of H-USY, H-beta, H-Y, H-ZSM-5,SBA-15, and combinations thereof.
 16. The one-step process of claim 10,wherein the Lewis acid catalyst and the Bronsted acid catalyst in thephysical mixture are present in a ratio of 95:5.
 17. The one-stepprocess of claim 15, wherein the H-USY has a surface area from 600 m²/gto 800 m²/g and a Si:Al ratio from 12 to
 30. 18. The one-step process ofclaim 10, wherein the alcohol is selected from the group consisting ofC1 to C10 alcohols, methanol, ethanol, propanol, butanol, hexanol,octanol, and mixtures thereof.